Watch: Shocking moment gang member grabs pen and attacks witness in court before being shot dead

This is the shocking moment a gang member on trial was shot dead when he launched himself onto a witness in an attempt to stab him.

Siale Angilau, a member of the Tongan Crips gang, was filmed grabbing a pen or pencil before running towards the witness, another gang member.

Court footage shows the witness sinking out of the way before a US Marshal shot Angilau, 25, four times.

Siale Angilau was shot dead after launching himself at a witness in court (AP)

The clip of the incident, that took place in 2014, has only now been released to the public, following pressure from outlets including the Salt Lake Tribune, after US District Judge John Dowdell dismissed a lawsuit brought by Angilau’s family claiming excessive force.

The judge wrote in a statement: ’The video completely contradicts the plaintiffs’ argument that Angilau stopped posing a danger within less than one second of launching himself over the witness stand while making a stabbing motion with a pen in his hand.’

In the clip, an officer can be heard yelling at Angilau: ‘Drop the pen, drop the pen out of your hand.’